This invention relates to an apparatus for controlling a machine tool and an industrial robot, and more particularly to a machine tool and industrial robot control apparatus which is highly suited for use in a system that includes a machine tool, a numerical control device for controlling the machine tool, an industrial robot, and a robot control device for controlling the industrial robot.
Many machine shops or factories employ systems that include a machine tool for machining a workpiece to prescribed specifications, and an industrial robot for executing various tasks such as the mounting of workpieces on the machine tool, the demounting of the workpieces from the machine tool, the exchanging of tools, and the cleaning of scraps produced by the machining operation. Ordinarily, such systems are provided with a numerical control device for controlling the machine tool, and with a separate control device for controlling the industrial robot. The numerical control device and the robot control device each incorporate a memory device, the memory device of the former storing a machining program which instructs the machine tool to machine the workpiece in a desired manner, and the memory device of the latter storing a robot command program which includes robot command data. In addition, both the numerical control device and the robot control device incorporate a processing unit. Each processing unit reads out sequentially the machining data and the robot command data from the corresponding memory device, and controls the machine tool or robot on the basis of the respective machining or robot control data so that the machine tool executes a prescribed machining operation and the robot a prescribed task in conformance with the particular command. The term "memory operation" is used in referring to the above system which comprises storing a machining program or robot command program in a memory device and then reading out sequentially the respective machining data or robot command data from the device.
In memory operation it is necessary to prevent the destruction or mutilation of the machining program and the robot command program in the event of an interruption in the power supply. To this end, each of the memory devices described above is composed of a high-capacity, non-volatile random access memory RAM (which shall be taken to include means in which a volatile RAM is backed up by a battery) such as a magnetic core or magnetic bubble memory. More specifically, in accordance with the prior art, a high-capacity, non-volatile memory is provided in both the numerical control device and the robot control device in the system described above. Moreover, in order to simplify the entering of data when an identical machining or robot operation is to be performed at some future date, a nonvolatile external storage medium such as a cassette-type magnetic tape, a cassette-type semiconductor memory, or a paper tape puncher is connected to each of the control devices so that the data stored in their respective memory devices can be preserved in the external storage media.
Thus it can be understood that the conventional system, including a numerically controlled machine tool and robot, is high in cost due to the requirement for two high-capacity, non-volatile memories and the corresponding two external storage units. The high price has inevitably impeded the wider use of robot systems.